Welcome Speech by Professor Chen-Ning Yang,Chairman of Board of Adjudicators

The Shaw Foundation Council is honored to award 3 Shaw Prizes for the year 2006:

The winners for the Astronomy Prize are Drs Saul Perlmutter, Adam Riess and Brian Schmidt for their discovery that the universe is accelerating in its rate of expansion. Ever since Einstein established the discipline of Cosmology in 1917, and Hubble found that the universe is expanding in 1929, the rate of expansion of the universe has been a central subject of research in Astronomy. To the international astronomy community, the discovery in 1998 that the universe is in fact accelerating in its rate of expansion was a profound shock. Implications of this discovery for physics, astronomy and philosophy will be a major subject of further research in future years.

The Life Science and Medicine Prize will be awarded to Dr Xiaodong Wang for his detailed study of the complicated biochemical mechanism for cell death. Before Wang's work, the mitochondria was regarded as only the energy source of cells. Wang found that in fact the mitochondria plays also an essential part in triggering cell death, opening the door to new areas of basic and therapeutic research.

This year's Mathematical Sciences Prize goes to Drs David Mumford and Wu Wentsun. Both winners started their careers in pure mathematics but in recent years have made separate major contributions to applied mathematics. Mumford's work are in pattern theory and vision research, while Wu's work are in computer proofs of propositions in geometry. The Shaw Foundation Council recognizes the increasing importance of mathematics in the increasing complexity of modern society, and is pleased to recognize great contributions by pure mathematicians to applied mathematics.

The discovery of extrasolar planets is one of the most dramatic and important findings in the history of Astronomy. For their roles in this development, Professor Michel Mayor of the University of Geneva and Professor Geoffrey Marcy of the University of California at Berkeley are awarded the Shaw Prize in Astronomy for 2005. Professor Mayor is being recognized for his discovery of the first planet around a normal star other than our own Sun. Professor Marcy is being recognized for his characterization of the masses and orbital properties of a large and statistically meaningful number of extrasolar planets and planetary systems.

The process of explaining the motions of the planets in our own Solar System spawned the Copernican Revolution. The later realization that stars are suns in their own right led to speculation that other planetary worlds might orbit distant suns. These speculations gained concrete foundation in 1995 when Mayor and Didier Queloz found a planet to orbit about the sunlike star, 51 Pegasi, with a 4-day period. The short period came as a shock because it meant that this giant planet, with about half of the mass of Jupiter, orbits its host star at a radius that is only 1% of the distance of Jupiter about our own Sun. Existing theories of planet formation held that giant planets should form in a rotating nebular disk surrounding a newly born star only beyond a so-called “frost line” where water vapor freezes and condenses out as solid ice. The exact location of the “frost line” at the time of giant planet formation is uncertain, but it should not have been much smaller than the present location of Jupiter, which is the innermost of the giant planets. The discovery of Mayor and Queloz electrified the field and spurred a huge increase in research activity on extrasolar planets, which has not abated to this day, ten years later.

Together with Paul Butler, Marcy quickly confirmed the reality of the 51 Pegasi planet using the method of precise Doppler measurement that he had developed for the purpose of extrasolar planet detection over many years. Seventy of the next 100 extrasolar planets discovered were found by his team. Many of these planets had distinctly non-circular orbits, in contrast with the orbits of known planets in our own Solar System. Several reside in systems where there is more than one giant planet, with multiple planets in a given system often having orbital periods that bear integer relationships to one another. As the observational sensitivity and the understanding of systematic errors steadily improve, planets with masses more like Saturn and Neptune are being found, instead of only the Jupiter-like bodies that characterized the initial discoveries. Significantly, there are no bodies that have masses appreciably in excess of 10 Jupiter masses. In a few cases, the orbital plane lies sufficiently edge-on to the observational line of sight that the giant planet transits in front of the host star, blocking out a small part of the star’s light, which allows an estimate of the radius of the transiting planet. A major surprise occurred in the latest such case where the combination of mass and radius implies that the planet has a dense rock-ice core that is seventy times the mass of the Earth, a much larger value than holds for any of the giant planets in our own solar system.

As the baseline for good orbital-period determinations passes the one decade mark, giant planets are being discovered with orbital distances from their host stars more akin to the case of our own Solar System. The stage is now being set for answering one of the most intriguing questions ever posed in science: how typical or atypical is our own Solar System? For moving this question from the dreamy realm of philosophical speculation to the concrete field of empirical fact, Michel Mayor and Geoff Marcy are justly honored tonight with the award of the Shaw Prize in Astronomy for 2005.

Speech by Professor Yuet Wai Kan,Chairman of Life Science and Medicine Selection Committee

Xiaodong Wang is the George L McGregor Distinguished Professor in Biomedical Science at the University of Texas Southwestern Medical School in the United States. Professor Wang is distinguished for his work on uncovering the biochemical and molecular process that leads to cell death. One might ask: Why is cell death important?

The human body is made up of ten trillion cells; each day billions of cells die and are replaced by new cells. Some of the well known examples are our blood cells, which are constantly being replaced by new cells from the bone marrow, or the cells in our intestines that are also constantly turned over. The birth and death of cells must be perfectly balanced, for, if cell birth exceeds death, organs enlarge and tumors may result. If death exceeds birth, organs atrophy as in some degenerative diseases such as Alzheimer's. There has been a great deal of study on the process that controls cell birth and development and much has been learned. On the other end however, cell death has been thought for a long time to be a random event, until the work of Robert Horvitz who used a worm model to demonstrate that there is a precise program that leads to cell death.

Professor Wang's contribution is his research on how this programmed cell death is carried out. The surprising discovery he made is that the mitochondrion plays an important role. Mitochondria are small structures within the cell. They contain genes that make enzymes to generate energy for biochemical reactions within the cell. What Professor Wang found was that when a cell is programmed to die, mitochondria release proteins that trigger cell death. One such protein, cytochrome C, has long been known to be an essential component in generating energy for the cells. Professor Wang discovered that cytochrome C has a novel function. It binds to another protein and activates an enzyme called caspase-3. Caspase-3 triggers a cascade of reactions that lead to the degradation of the DNA in the cell nucleus, the break up of the cell membrane and the death of the cell. Professor Wang also discovered several other proteins that held this process in check so that cell renewal is regulated in an orderly manner.

What is the importance of Professor Wang's discovery? Based on his elucidation of this biochemical pathway, drugs are being developed to influence this process. For example, to minimize cell injury after a heart attack or a stroke, drugs are being sought to block the mitochondrial proteins that cause cell death. At the opposite spectrum, cancer cells often prevent cell death by overproducing proteins that block cell death, thereby allowing the cancer cells to proliferate. Approaches are being developed to overcome this blockage. Thus Professor Wang's work has opened a field of research into treatment that may benefit a whole host of devastating human diseases.

Mathematicians were prominent in the development of the computer, from the early 19th centruy ideas of Charles Babbage to the modern fundamental work of Alan Turing and John von Neumann in the middle of the 20th century. But computer science has now developed into a vastenterprise and the close connection with mathematics is in danger of being lost, to the detriment of both.

David Mumford and Wu Wen-Tsun are two leading mathematicians who have, in the second part of their careers, re-established that link in two different ways.

Mumford, who made outstanding contributions to the classical subject of algebraic geometry, has applied sophisticated mathematical analysis to the subject of computer vision. This tries to mimic by computer the complex process by which human beings see and understand the world around us.

Wu Wen-Tsun began as a geometer (under the great Shing-Shen Chern, the first recipient of the Shaw Prize in mathematics) but went in the opposite direction to Mumford, showing how to develop effective computer algorithms for the automatic proof of theorems in geometry.

It is notorious that computers, which are digital machines, are not well adapted to spatial processes, so that bridging the gap between the computer and geometry or vision as Mumford and Wu have done is a great achievement. They represent a new role model for mathematicians of the future and are deserved winners of the Shaw Prize.